The femoral cartilage eventually pushes "through" the tibial cartilage and they wind up overlapping, hence the negative jacobian and resulting errors.ĭoes anyone have any insight on this? It isn't the boundary condition on the tibial cartilage- i've double and triple checked that its ONLY the underside surface, and nowhere else. When examining the results in postview, I notice the femoral component is deforming as expected, but the tibial cartilage exhibits no deformation _at all_. The model runs in a reasonable amount of time, but always ends with error termination as negative jacobians are detected for time points. My boundary conditions no movement at all on the lower surface of the tibial cartilage (where it would contact bone) and z only movement on the opposite femoral cartilage side (again, where it wound contact bone.) On the articulating surfaces, I have an sliding elastic contact interface with a penalty of 1000, and frictional coefficient of 0.02. Cartilage contact stress in retroverted hips for all subjects and loading scenarios. The fringe plots shown in the walking mid, descending stairsand chair rise rows were averaged to create Figure 5. Both the femoral and tibial components are treated this way. Cartilage contact patterns were subject-specific, but tended to be fairly distributed over the articular surface. The cartilage is modeled as neo-hookean with a density of 1100kg/m^3, 3.3MPa stiffness, and 0.4 poissons. As I am examining a steady-state loading plateau, I am neglecting viscoelasticity or any fluid flow, purely matrix stiffness. I have designed idealized geometry of the medial size of the femoral cartilage above the tibial cartilage. I am in the process of modeling the medial half of the knee for a cartilage contact problem. This release contains many improvements, such as better performance of the reactive viscoelastic framework, faster startup of FSI models, box constraints for constrained levmar optimization, new rendering features, and more. FEBio Studio 1.8 has been released! It comes with FEBio 3.7.
Cartilage contact visualization postview colin smith software#
The FEBio software downloads and knowledgebase can be found here. This will allow you to stay up to date on recent activity on the forum. You can subscribe to forums by pressing the "Subscribe" button at the top of the forum. Human articular cartilage: influence of aging and early symptomatic degeneration on the spatial variation of T2-prelimenary findings at 3T. CrossRef Google Scholar Mosher TJ, Dardzinski BJ, Smith MB (2000). Moderators are here to assist with explaining novel features, addressing bug reports and reviewing feature requests, but the effectiveness of the forum depends critically on the participation of experienced users who can assist novices or share ideas and models that explore challenging problems. Osteoarthritis and Cartilage, Volume 15, Issue 7, Pages 789797. A broad level of participation is encouraged, to create a vibrant community that helps improve the quality and usefulness of these open-source/free software products. Forum participants are encouraged to post questions, as well as answer posts from others. This forum serves the community of FEBio and FEBio Studio users and developers.
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